Electric motor mounted magnetic friction brake



g- 1967 H. E. KLINKENBERG ETAL 3,

ELECTRIC MOTOR MOUNTED MAGNETIC FRICTION BRAKE;

Original Filed July 27, 1964 b g f in Ken big United States Patent3,338,349 ELECTRIC MOTOR MOUNTED MAGNETIC FRICTION BRAKE Hubert E.Klinkenberg and Leroy W. Simonson, Beloit, Wis., assignors to WarnerElectric Brake & Clutch Company, South Beloit, 111., a corporation ofDelaware Continuation of application Ser. No. 544,519, Apr. 22, 1966,which is a division of application Ser. No. 385,190, July 27, 1964. Thisapplication Nov. 17, 1966, Ser. No. 607,101

Claims. (Cl. 188161) This application is a continuation of our copendingapplication Ser. No. 544,519, filed Apr. 22, 1966, which, in turn, is adivision of our application Ser. No. 385,190 filed July 27, 1964 and nowabandoned.

This invention relates to a self-contained magnetically energizablebrake which is adapted to apply a retarding torque to the shaft of anelectric motor and to be supported from the end bell thereof.

The primary object is to provide a wholly enclosed magnetic brake whichbecomes coupled to the motor shaft automatically as an incident tobringing its casing into abutment with and securing the same to themotor end bell.

A more detailed object is to apply the braking torque to a ringjournaled in the brake casing and adapted to telescope onto and becomecoupled to the shaft of a motor having a shaft and end bell of aconfiguration standardized by the National Electrical ManufacturersAssociation (NEMA).

Other objects and advantages of the invention will become apparent fromthe following detailed description taken in connection with theaccompanying drawings, in which FIGURE 1 is a fragmentary elevationalview of an electric motor equipped with a magnetic friction brakeincorporating the novel features of the invention and shown as adiametrical section taken along the line 11 of FIG. 2.

FIG. 2 is an end view.

FIG. 3 is a view similar to FIG. 1 with the brake and motor casingsseparated.

In the form illustrated in the drawings, the brake embodying the presentinvention is especially adapted for mounting on the bell on the end ofthe housing of an electric motor of standard construction. In end bellsof the Type C type, a cylindrical male pilot surface 11 projects from aflat end 12 and is precisely concentric with the projecting end 13 ofthe motor shaft which is of standard size and length and equipped with akey 14 of standard dimensions. In most of the Type C NEMA end faces, thepilot surface is smaller than the circle around which threaded boltholes 15 are spaced angularly and equidistantly.

The operating parts of the improved brake are mounted on and enclosed bya casing in the form of a ring 16 of general cup shape having an innerflange 17 defining the cup bottom having a central opening 18 thereinand an outer longer flange 19, both flanges being concentric with theaxis of the cup. The ring is adapted to be clamped against the end hellwith the end 28 of the outer flange 19 abutting against the surface 12.Herein this is accomplished by screws 50 disposed in parallel holes 51extending through the outer flange 19 and spaced radially and angularlyto match the holes 15 in the motor end bell. The screws thread intothese holes and the heads 52 are preferably set beneath the outer endsurface of the casing.

Disposed within the inner flange 17 and journaled in a bearing 20supported thereby is a tubular ring or sleeve 3,338,349 Patented Aug.29, 1967 'ice 24, 26 which supports the rotary part of the brake at itsinner end and is contoured internally to receive the projecting endportion of the motor shaft 13 and become spline coupled theretoautomatically in the movement of the casing 16 axially from the positionshown in FIG. 3 into abutment of the flange end 28 with the end surface12 of the motor end bell. In such movement, the shaft end telescopesinto the recess 27 in the ring and the key 14 on the shaft 13 slidesinto a groove 30 in the ring which herein is composed of two abuttingrings 24, 26 clamped together by screws 25. The length of the casingflange 19 is such that the motor shaft 13 will enter the recess 27 andbecome coupled to a desired length of the key 14 as the flange 19 comesinto abutment with the end bell.

Herein, the part 24 of the coupling ring 24, 26 is the enlarged endportion of, a shaft 22 which projects outwardly through and beyond thebottom of the casing cup and constitutes an extension of the motor shaftwhich may be coupled through a key and slot 23 to a part to be driven bythe motor. When the coupling ring 24, 26 is thus extended, the shaft 22is journaled in a second bearing 20 axially spaced from the bearing 20and disposed near the bottom end of the casing cup 16. When a separateoutput shaft 22 is not required, the rotary sleeve 24, 26 may be leftopen at its outer end and supported by the bearing 20 alone.

The end 2'8 of the outer flange 19 is somewhat larger than the malepilot 11 provided on a standard NEMA motor. Thus, after telescoping ofthe rotatable ring 24, 26 onto the motor shaft and abutment of theflange end with the motor end bell as above described, the casing 16will be supported and located transaxially by the motor shaft free ofthe pilot 11. This avoids any possi bility of objectionable loading ofthe bearings 20.

The magnetic friction brake indicated generally at 29 includes a magnet31 fixed to the cup 16 between the flanges 17 and 19 and providing afriction surface 39 facing axially toward the open end of the cup anddisposed about midway between the ends thereof. A flat armature ring 34splined onto the inner end portion of the rotatable ring 24, 26 isadapted to be drawn into axial gripping engagement with the magnet 31upon energization of a multi-turn winding 37 of the magnet. The lattersurrounds the inner flange 17 onto which its core 32 of U-shapedcross-section ispressed or otherwise secured. The concentric inner andouter pole pieces of the core are spanned at their ends by a ring orseries of segments 33 of wear resistant friction material cooperatingwith the end faces 35 of the pole pieces to form the friction face 39which is disposed about midway between the ends of the cup 16.

The armature ring 34 of iron has angularly spaced and inwardlyprojecting radial teeth 38 fitting closely in but slida'ble along splinegrooves 40 angularly spaced around the exterior of the ring 26 which maybe composed of molded plastic material and preferably is disposedinwardly beyond the race rings of the bearing 20 and is somewhat largerthan the latter.' The armature is positioned axially along the grooves40 by devices 41 which operate automatically in service use to take upwear at the friction faces of the brake and maintain a uniform gap ofthe desired narrow axial width between these faces when the brake isdisengaged by deenergization of the magnet. These devices may takevarious forms including the one fully disclosed in the parent of thisapplication. In general, the devices here shown each comprise a clip ofresilient steel having upstanding flanges 42 and 43 spaced apart attheir lower ends a distance greater than the thickness of the armature34 by the width of the air gap desired to be maintained. There is oneclip for each of the collar grooves 40 fitting snugly therein with theflanges thereof engaging opposite sides of the armature.

When the armature is attracted to the magnet face, it is shifted awayfrom the short flange and against the longer flange thus bending thelatter. If wear has taken place, the armature will engage the flange 42before it does the magnet poles. As a result, the friction between theclip and the groove Walls is overcome, and the armature and clip as aunit are shifted along the grooves. Then, when the magnet isdeenergized, the spring 42 pushes the armature away from the magnet andthe flange 42 and against the flange 43 thus establishing the gap of thede sired width.

It will be apparent that the improved motor brake is a self-containedunit of simple and inexpensive construction and adapted for quick andeasy assembly Onto and rigid attachment to the motor end bell ofstandard construction. In the assembly, the motor shaft enters therecess 27 in the rotatable ring 24, 26 and becomes coupled to this ringautomatically as the casing 16 is brought into end abutment with the endbell of the motor. Thereafter, itis ony necessary to aline the holes 51in the casing With the holes 15 on the end bell and insert and tightenthe screws 50. By providing for telescoping of the motor shaft into therecess 27, optimum axial compactness is achieved in the arrangement ofthe bearings 20 and the brake and coupling parts.

We claim as our invention:

1. An electromagnetic friction brake adapted to be mounted on anelectric motor having a shaft with a key therein projecting from themotor end bell and an annular series of angularly spaced holesconcentric with said shaft and extending into said end bell near theouter periphery thereof, said brake comprising a cup-shaped casinghaving generally cylindrical inner and outer flanges concentric withsaid shaft, said outer flange being longer than the inner flange andadapted to abut said motor end, and said inner flange defining acentralopening in the bottom of the cup, parallel angularly spaced holesextending through said casing and adapted to register with said end bellholes and receive fastening elements for clamping the'casing to said endbell, an output shaft extending through said casing, opening .andjournaledintermediate its ends in said inner flange, the inner end ofsaid shaft being -spaced inwardly from the end of said outer flange andhaving an axially opening recess therein internally contoured to receivethe end portion of said motor shaft in spline coupled relation as anincident to abutment of the end of said outer flange and said end belland alinement of said holes with said motor screws holes, the other endportion of the shaft projecting through and outwardly from the center ofsaid casing, an annular magnet disposed between said inner and outerflanges and including a magnetic core of U-shaped radialcross-sectionsecured to said casing ring between said flanges andproviding radiallyspaced pole faces facing axially toward the open endof the casing and disposed intermediate the end 'of said outer flange,and an armature ring splined onto the inner end portion of said shaftand spanning the pole faces to form with the core a magnetic fluxcircuit of toroidal shape. j

2. An electromagnetic friction brake adapted to be mounted on anelectric motor having a shaft with a key therein projecting from themotor end bell and an annular series of angularly spaced holesconcentric with said shaft and extending into said end bell near theouter periphery thereof, said brake comprising a cup-shaped casinghaving a central bottom opening and a generally cylindrical outer flangeconcentric with the cup axis and adapted to abut said end bell, parallelangularly spaced holes extending through said casing and adapted toregister with said motor holes and receive fastening elements forclamping the casing against the end bell, an output shaft extendingthrough said casing opening and journaled intermediate its ends in thecup bottom, the inner end of said shaft being spaced inwardly from theend of said outer flange and having an axially opening recess thereininternally contoured to receive the end portion of said motor shaft andbecome spline coupled thereto as an incident to abutment of the end ofsaid outer flange with said end bell and alinement of said casing andend bell holes, the other end portion of the shaft projecting throughand outwardly from the center of said casing, an annular magnet disposedbetween said inner and outer flanges and including a magnetic core ofUshaped radial cross-section securedto said casing ring between saidflanges and providing radially spaced pole faces facing axially towardthe ,open end of the casing and disposed intermediate the ends of saidflange, and an armature ring splined onto the inner end portion of saidshaft and spanning the pole faces to form with the core a magnetic fluxcircuit of toroidal shape.

3. An electromagnetic friction brake adapted to be mounted on anelectric motor having a shaft with a key therein projecting from themotor end bell and an annular series of angularly spaced holesconcentric with said shaft and extending into said end bell near theouter periphery thereof, said brake comprising a generally cup-shapedcasing having generally cylindrical inner and outer flanges concentricwith said shaft, said outer flange being longer than the inner flangeand adapted to abut said motor end, and said inner flange defining acentral opening in the bottom of the cup, parallel angularly spacedholes extending through said casing and adapted to register with saidend bell holes and receive fastening elements for clamping the end ofsaid outer flange to said end bell, a tubular ring disposed in saidcasing opening and journaled intermediate its ends in said inner flange,said ring opening axially and being internally contoured to receive andtelescope with the end portion of said motor shaft in spline coupledrelation automatically as an incident to abutment of the end of saidouter flange and said end bell and alinement of said holes with saidmotor holes whereby the final transaxial position of said ring and saidcasing is determined solely by said motor shaft, an annular magnetdisposed between said inner and outer flanges and including a magneticcore of U-shaped radial cross-section secured to said casing betweensaid flanges and providingradially spaced pole faces facing axiallytoward the open end of the casing and disposed intermediate the ends ofsaid outer flange, and an annular armature encircling and splined ontothe inner end portion of said ring and spanning said pole faces to formwith said core a magnetic flux circuit of toroidal shape.

4. An electromagnetic friction brake as defined in claim 3 in which saidring is journaled in a bearing supported by said inner flange anddisposed in the plane of said magnet,

and said armature is supported on an end portion of said ring projectingaxially beyond said bearing.

5. An electromagnetic friction brake as defined in claim 3 in which themotor shaft, when'said casing and end bell are in abutment projectsaxially through said magnet core.

References Cited UNITED STATES PATENTS 2,970,681 2/1961 Timmcke 188164 XDUANE A. REGER, Primary Examiner.

3. AN ELECTROMAGNETIC FRICTION BRAKE ADAPTED TO BE MOUNTED ON ANELECTRIC MOTOR HAVING A SHAFT WITH A KEY THEREIN PROJECTING FROM THEMOTOR END BELL AND AN ANNULAR SERIES OF ANGULARLY SPACED HOLE CONCENTRICWITH SAID SHAFT AND EXTENDING INTO SAID END BELL NEAR THE OUTERPERIPHERY THEREOF, SAID BRAKE COMPRISING A GENERALLY CUP-SHAPED CASINGHAVING GENERALLY CYLINDRICAL INNER AND OUTER FLANGES CONCENTRIC WITHSAID SHAFT, SAID OUTER FLANGE BEING LONGER THAN THE INNER FLANGE ANDADAPTED TO ABUT SAID MOTOR END, AND SAID INNER FLANGE DEFINING A CENTRALOPENING IN THE BOTTOM OF THE CUP, PARALLEL ANGULARLY SPACED HOLESEXTENDING THROUGH SAID CASING AND ADAPTED TO RESISTER WITH SAID END BELLHOLES AND RECEIVE FASTENING ELEMENTS FOR CLAMPING THE END OF SAOD OUTERFLANGE TO SAID END BELL, A TUBULAR RING DISPOSED IN SAID VASING OPENINGAND JOURNALED INTERMEDIATE ITS ENDS IN SAID INNER FLANGE, SAID RINGOPENING AXIALLY AND BEING INTERNALLY CONTOURED TO RECEIVE AND TELESCOPEWITH THE END PORTION OF SAID MOTOR SHAFT IN SPLINE COUPLED RELATIONAUTOMATICALLY AS AN INCIDENT TO ABUTMENT OF THE END OF SAID OUTER FLANGEAND SAID END BELL AND ALINEMENT OF SAID HOLES WITH SAID MOTOR HOLESWHEREBY THE FINAL TRANSAXIAL POSITION OF SAID RING AND SAID CASING ISDETERMINED SOLELY BY SAID MOTOR SHAFT, AN ANNULAR MAGNET DISPOSEDBETWEEN SAID INNER AND OUTER FLANGES AND INCLUDING POSED BETWEEN SAIDINNER AND OUTER FLANGES AND INCLUDING TO SAID CASING BETWEEN SAIDFLANGES AND PROVIDING RADIALLY SPACED POLE FACES FACING AXIALLY TOWARDTHE OPEN END OF THE CASING AND DISPOSED INTERMEDIATE THE ENDS OF SAIDOUTER FLANGE, AND AN ANNULAR ARMATURE ENCIRCLING AND SPLINED ONTO THEINNER END PORTION OF SAID RING AND SPANNING SAID POLE FACES TO FORM WITHSAID CORE A MAGNETIC FLUX CIRCUIT OF TORODIAL SHAPE.